Cambridge

Cambridge
Developer(s)	Joe Zeng
Platform(s)	Windows, macOS, Linux
Release	May 2019
Latest release	v0.1.3 (June 16, 2019)
Gameplay info
Next pieces	variable
Playfield size	10 × 24, 20 visible rows
Hold piece	Yes, with IHS
Hard drop	All variants supported
Rotation system	Classic ARS, Ti-ARS, SRS, Cambridge

Cambridge is a Lua-based falling-block-game engine dedicated to creating a robust, easily customizable platform for creating new, custom game modes.

The first public release of Cambridge coincided with the first Carnival of Darkness.

Game modes

These game modes are exclusive to, or originated from, Cambridge:

• Marathon 2020
• Survival 2020
• Strategy
• Interval Training
• TetrisGram™ Pacer Test

These game modes from other creators are also supported:

• Demon Mode, created by Oshisaure
• Phantom Mania, originally from Nullpomino
• Phantom Mania 2

And these modes from published Tetris games:

• Ligne (40 lines mode)
• Marathon A1 (Tetris The Grand Master)
• Marathon A2 (Master mode from Tetris The Absolute The Grand Master 2)
• Marathon A3 (Master mode from Tetris The Grand Master 3 Terror-Instinct)
• Survival A1 (20G mode from TGM)
• Survival A2 (Death mode from TAP)
• Survival A3 (Shirase mode from Ti)
• Line Attack (Another mode from Ace)

Marathon 2020

Marathon 2020 is Cambridge's own "Master" game mode, that endeavours to take the level-based game system from the TGM series up to 20 (twice), in celebration of the year 2020.

Gameplay

The goal of this mode is to reach level 2020. Every piece placed increases the level by 1, and every line cleared also increases the level by 1, with bonuses for large numbers of lines:

Level Bonuses

Lines cleared	Levels advanced
1 (single)	1
2 (double)	2
3 (triple)	4
4 (tetris)	6

When the current level reaches one less than the level at the bottom of the display (usually a multiple of 100), the level will not advance until a line is cleared.

Levels

Each section is 100 levels long, except for the last section, whose levels go from 1900 all the way to 2020.

However, it is possible to be stopped early on if you do not play fast enough.

Torikans

There are certain checkpoints at which your current time will be checked and you will be stopped if your time is over a set objective time.

Level	Time limit
500	06:00:00
900	08:30:00
1000	08:45:00
1500	11:30:00
1900	13:15:00

At levels 500, 1000, and 1500, you will be stopped immediately if your time is not under the objective.

At level 900, the next section will be capped at 999, and you will get a short credit roll when the last section is over.

At level 1900, the next section will be capped at 2000, and you will be stopped immediately with no credit roll.

Speed

Marathon 2020 gets faster in two different, independent ways, the gravity curve and the delay curve.

The gravity curve is always the same at a particular level, while the delay curve can vary based on your previous section time.

Gravity Curve

The gravity curve is the same as it is in the original TGM and TAP.

Internal Gravity

Level	Internal Gravity (1/256 G)	Level	Internal Gravity (1/256 G)
0	4	220	32
30	6	230	64
35	8	233	96
40	10	236	128
50	12	239	160
60	16	243	192
70	32	247	224
80	48	251	256 (1G)
90	64	300	512 (2G)
100	80	330	768 (3G)
120	96	360	1024 (4G)
140	112	400	1280 (5G)
160	128	420	1024 (4G)
170	144	450	768 (3G)
200	4	500	5120 (20G)

Delay Curve

The delay curve is shown as in the following table. Line ARE is always equal to ARE.

Level	ARE	Lock	DAS	Line	Cool
0	27	30	15	40	45.00
100	24	30	12	25	41.50
200	21	30	12	25	38.50
300	18	30	9	20	35.00
400	16	30	9	15	32.50
500	14	30	8	12	29.20
600	12	26	8	12	27.20
700	10	22	8	8	24.80
800	8	19	7	8	22.80
900	6	17	7	6	20.60
1000	6	15	6	6	19.60
1100	6	15	6	4	19.40
1200	6	15	6	4	19.40
1300	5	15	5	4	18.40
1400	5	15	5	2	18.20
1500	4	15	4	2	16.20
1600	4	13	4	2	16.20
1700	4	11	4	2	16.20
1800	4	10	4	2	16.20
1900	4	9	4	2	16.20
2000	4	8	3	2	15.20

The delay curve always advances at least 1 level at or above level 500, and if you get a section cool when the level is 500 or higher, it will advance 2 levels instead. This means that you can reach the maximum delay level of 2000 as early as level 1200, after which it will stay at 2000 until the end of the game.

Section COOL

If your time in a particular section from 0 to 70 is smaller than the "cool" requirement at that level on the delay curve, your delay curve will be bumped up an extra level at the end of the section.

In order to get a section cool, your 0-70 section time must be below the cutoff and no more than 2 seconds slower than your previous 0-70 time.

Grading

Grades in Marathon 2020 are represented as number ranging from 0 to 50, then GM. It is currently unknown how the GM grade is obtained.

Basic grades

Internally, the grade counter is a number that can range from 0 to 30.

At the beginning of the game, it starts at 0. To increase it, you must bring an internal grade point counter past a certain threshold.

The threshold is set at 50 points for the first grade, then 100 more points for the next grade, then 150 points for the grade after that, and so on. You reach the maximum level of 30 at a total of 23,250 points.

A table of the thresholds in grade points required to reach each level is provided below:

Grade	Threshold
0	0
1	50
2	150
3	300
4	500
5	750
6	1050
7	1400
8	1800
9	2250
10	2750
11	3300
12	3900
13	4550
14	5250
15	6000
16	6800
17	7650
18	8550
19	9500
20	10,500
21	11,550
22	12,650
23	13,800
24	15,000
25	16,250
26	17,550
27	18,900
28	20,300
29	21,750
30	23,250

Points are given according to a different scale, the point level. The point level is calculated by taking your current actual level, and adding the delay level to it.

The points given for clearing certain amounts of lines is given as follows at particular point levels:

Point level	Single	Double	Triple	Tetris
0	10	20	30	40
100	10	20	30	40
200	10	20	30	48
300	10	20	30	60
400	10	20	36	72
500	10	21	42	84
600	10	24	48	96
700	10	27	54	108
800	10	30	60	120
900	11	33	66	140
1000	12	36	72	160
1100	13	39	81	180
1200	14	42	90	200
1300	15	45	99	220
1400	16	48	108	240
1500	17	52	117	260
1600	18	56	126	280
1700	19	60	135	300
1800	20	64	144	320
1900	21	68	153	340
2000	22	72	162	360
2100	23	76	171	380
2200	24	80	180	400
2300	25	84	189	420
2400	26	88	198	440
2500	27	92	207	460
2600	28	96	216	480
2700	29	100	225	500
2800	30	104	234	520
2900	31	108	243	540
3000	32	112	252	560
3100	33	116	261	580
3200	34	120	270	600
3300	35	124	279	620
3400	36	128	288	640
3500	37	132	297	660
3600	38	136	306	680
3700	39	140	315	700
3800	40	144	324	720
3900	41	148	333	740

Past level 1000, a 4-line clear will always give (30 * current grade), regardless of point level.

The remaining 20 grades come from section cools. Every section cool you get boosts your score by one grade. There are no regrets.

Points are also taken away with the time it takes to lock down a piece. The delay counter starts at 0, and increases by (current grade + 2) every frame. When the counter reaches or exceeds 240, it resets to 0, and 1 grade point is taken away.

Grades are based on the maximum grade points achieved. Once a grade has been attained, it cannot be lost even if grade points drop below the threshold for that grade.

Survival 2020

Survival 2020 is the Death mode to Marathon 2020's Master mode, and introduces a new mechanic known as total delay. If your piece has been active for the length of the total delay, it will lock down regardless of how much lock delay the piece had on move or step reset.

Strategy

Strategy Mode flips the normal "figure out where to place a piece as you move it" logic of Tetris inside-out. In Strategy mode, most of your time is spent waiting for pieces before executing a fast sequence of inputs to get them where you want them to go.

The goal of the game is to get to level 999, just like TGM, except with the following speed curve:

Delays

Level	ARE/Line clear (frames)	Lock (frames)	DAS (frames)
000-099	60	8	6
100-199	54	8	6
200-299	48	8	6
300-399	42	8	6
400-499	36	8	6
500-599	30	6	6
600-699	24	6	6
700-799	21	4	6
800-899	18	4	6
900-999	15	4	6

Interval Training

Interval Training is a mode specifically for players who are attempting to break the 2:28 torikan in Survival A3, or play more consistently at the top speed bracket in Marathon A3.

The game will stay at the same speed level throughout, which is the top speed level in Master mode, or the level 300 speed level in Shirase:

Delays

Speed level	ARE (frames)	Line ARE (frames)	DAS (frames)	Lock (frames)	Line clear (frames)
0 - unlimited	6	6	7	15	6

The time limit is 30 seconds per section, and resets to 30 seconds (without adding the unused time from the previous section) at the beginning of a new section. Players play until they top out or run out of time in a single section. There is no maximum level — play can continue infinitely as long as the player can manage under 30 seconds per section consistently.

TetrisGram™ Pacer Test

The TetrisGram™ Pacer Test is a multi-stage piece-placing capacity test that progressively gets more difficult as it continues. In each segment, you must clear 3 lines. The line-clearing speed starts slowly, but gets progressively faster each minute after you hear a particular signal. Each segment is marked with with a different signal. The second time in a row you fail to clear 3 lines before the segment marker sound, your game is over.

Phantom Mania 2

Phantom Mania 2 is a successor to Nullpomino's Phantom Mania. Just like Phantom Mania is based on Speed Mania, Phantom Mania 2 is based on Speed Mania 2 (known in Cambridge as Survival A3).

Gameplay

The goal of this game is to reach the end at level 1300, and then score as many grades as possible in the ending credit roll.

Each piece disappears as soon as it is placed down. Only the active piece is visible at any given time.

Levels work the same way as the A3 games or Marathon 2020.

When the current level reaches one less than the level at the bottom of the display (usually a multiple of 100), the level will not advance until a line is cleared.

Levels

Each section is 100 levels long. At certain levels, the speed may get faster, or the difficulty may increase some other way.

Level	What happens
500	Rows of garbage start to advance on the board. The bottom row is copied, appearing for a brief flash before disappearing again.
1000	The garbage stops, but the hold queue turns invisible, and the pieces start to use bone blocks.
1100	The first next preview turns invisible.
1200	The second next preview turns invisible.

Unlike in Survival A3, the speed of the game does not get faster past level 1000.

Torikans

There are certain checkpoints at which your current time will be checked and you will be stopped if your time is over a set objective time.

Level	Time limit
300	2:02.00
500	3:03.00
800	4:45.00
1000	5:38.00

If you hit one of these torikans, the field will suddenly turn visible, marking the end of the game, and a 30-second credit roll will play.

If instead you reach level 1300, an invisible Big-mode credit roll will play.

Grading

Your grade starts at 1, and goes on from S1 to S9, and then M1 upwards indefinitely.

Your grade advances each section based on your section time. If you achieve a section COOL, you get 2 grade points. If you instead incur a section REGRET, you get no grade points. The normal section time (in between COOL and REGRET) is worth one grade point.

Level	Section COOL	Section REGRET
000-499	36.00	48.00
500-999	30.00	39.00
1000-1299	27.00	35.00

Then, the invisible roll at the end of level 1300 is also worth grade points.

Lines cleared	Grade points
1	0.02
2	0.06
3	0.15
4	0.40
Clear	1.00

The number of grade points you earn correspond to your grade as follows:

Points	Grade
0	1
1	S1
2	S2
3	S3
4	S4
5	S5
6	S6
7	S7
8	S8
9	S9
10	m1
11	m2
12	m3
13	m4
14	m5

And so on. For x > 9 grade points, your grade is m(x-9).

If you achieve a section COOL on each section, your rank will be m17 entering the credit roll.

Delay Timing

Cambridge counts delay timing differently from either Nullpomino or the original TGM games. The timings are based on making it easy to add up the times for delays without running into fencepost errors.

• ARE is counted from the first frame that a piece locks to the first frame that the next piece appears.

• • For example, if a piece is locked at 01:35.08 and ARE is 30, the new piece will appear at 01:35.58 (exactly 30 frames later).

• Line delay is counted from the first frame that a piece locks to the first frame that the lines appear cleared.

• Line ARE is counted from the first frame that lines appear cleared to the first frame that the next piece appears.

• • For example, if a piece is locked at 01:35.08 and clears a line, Line delay is 40, and Line ARE is 27, the line will finish clearing at 01:35.75 (40 frames later) and the next piece will appear at 01:36.20 (27 frames later).

• DAS is counted from the first frame that the piece moves to the first frame that the piece moves again.

• Lock delay is counted from the first frame that a piece touches the ground to the first frame that a piece locks.

When counted this way, the delays in several of the TGM games are different from the delays that are stored in memory.

• ARE generally has two frames added to account for one frame of lock flash and an extra frame where the ARE counter is 0 before the new piece enters.

• DAS generally has one frame added because the autorepeat starts the frame after the DAS counter reaches the limit.

Given below are the speed ratings programmed into the various games:

Marathon/Survival A1

Speed level	ARE (frames)	Line ARE (frames)	DAS (frames)	Lock (frames)	Line clear (frames)
0 - 999	30	27	15	30	44

Marathon A2

Speed level	ARE (frames)	Line ARE (frames)	DAS (frames)	Lock (frames)	Line clear (frames)
0 - 499	27	27	15	30	40
500 - 599	27	27	9	30	25
600 - 699	27	18	9	30	16
700 - 799	18	14	9	30	12
800 - 899	14	8	9	30	6
900 - 999	14	8	7	17	6

Survival A2

Speed level	ARE (frames)	Line ARE (frames)	DAS (frames)	Lock (frames)	Line clear (frames)
0 - 99	18	14	11	30	12
100 - 199	14	8	11	26	6
200 - 299	14	8	10	22	6
300 - 399	8	8	9	18	6
400 - 499	7	7	7	15	5
500 - 999	6	6	7	15	4

The primary difference between these delays and the delays from the original game is that Cambridge does not exclude any frames when charging DAS. Every frame that a direction is held increases the DAS counter by 1, while some frames are "dead zones" for DAS charging in the original games.